Roller-boring drill.



H. B. HUGHES. T ROLLER BORING DRILL.

Patented June 17, 1919.

UNITED STATES PATENT" OFFICE.

HOWARD R. HUGHES, 0F. HOUSTON, TEXAS, ASSIGN'OR T0 SHARP-HUGHES TOOLGOMPAN Y, OF HOUSTON, TEXAS, A CORPORATION OF HOLDER-BORING DRILL.

Specification of Letters Patent. Patented June 17, 1919.

Application filed April 10, 1 )13. Serial No. 760,167.

To all whom. it may concern:

Be it known that I, HOWARD R. HUGHES, a citizen of the United States,residing at H ouston; Texas, have invented a certain new and usefulImprovement in Roller-Boring Drills, of which the following is a full,clear, and exact description, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to roller boring drills.

One object of the invention is to provide a strong and efficient rollerboring drill that can be manufactured at a low cost.

Another object is to provide a roller boring drill of novel design thatwill underream a hole. v v

' And still another object is to provide an underreaming drill havingcutting rollers which are so arranged that the drill will seat itself ina tapered recess at the bottom of the hole being formed, therebyinsuring a circular hole of approximately uniform diameter. Otherobjects and desirable features of my invention will be hereinafterpointed out.

Figure 1 of the drawings is a side elevational view partly in verticalsection of a roller boring drill constructed in accordance with myinvention;

Fig. 2 is a bottom plan view of said drill;

Fig. 3 is a vertical sectional view taken at right angles to Fig. 1; and

Fig. 4 is a detail sectional; view illustrating a slight modification ofmy invention.

Referring to the drawings which illustrate the preferred form of mypresent invention, A designates the head of the drill which ispreferablyformed in one piece and provided at its upper end with a screwthreadedboss 1 to which the hollow drill stem, not shown, is connected. Aringshaped fl. nge 2 is also provided at the upper end of the head so asto support a lubricant holder, not shown. Two cutting rollers B and Oare arranged diametrically opposite each other in a pocket in the headon spina d lesthat project downwardly and inwardly toward thelongitudinal axis of the head,-

anda rotatable cutting means is arranged horizontally between therollers B and C so as-to disintegrate thematerial at the center of thehole being formed. In the preferred form of my invention as herein shownthe horizontallyarranged cutting means just referred to consists of aplurality of slightly I side of the center rollers D with their largeends butting against the small ends of said rollers D. All of saidrollers D and E are provided with chisel-teeth 6' which extend parallelto the shaft 3 on which said rollers turn, andwashers 7 are preferablyinterposed between said rollers and also between the end rollers and theshaftbearings on the drill head. It is immaterial, however, so far as mybroad idea is concerned what particular kind of cutting surface therollers D and E are provided with. By arranging the rollers D and E inthe manner above-described I obtain a substantially cylindricalshapedcutting device that tapers slightly in opposite directions from itsmiddle to its ends and which will form a tapered coneshaped recess atthe center of the liOle when the drill is in operation. The side rollersB andO distintegrate the material atthe bottom of the hole that liesoutside of the path of the center rollers D and E, and said side rollersalso shear off the material from the vertical side wall of the hole. Inthe preferred form of my invention, as herein shown, each of the rollersB and O is provided with two sets of radially-disposed chisel-teeth 8and 9 which are disposed at approximately right angles to each otherwhen the drill is in service. The teeth 8 of each roller extend atapproximately an acute angle to the inner end face of'the roller, and inView of the fact that the'roller is mounted on a spindle which projectsdownwardly and inwardly toward the longitudinal center of thedrill-head, said teeth 8 are disposed at approximately right angles tothe longitudinal axis of the drill. The portions of the rollers B and Con which the teeth 8 are formed are substantially frusto-conicalshapeand they are so arranged that th 'ir vertices terminate at thelongitudinal center tegrate the material without slipping or draggingover the material.

The frusto-conical-shaped portion of the roller C on which thechiselteeth 8 are formed is slightly larger than the correspondingportion of the roller B so that the teeth 8 of the roller 0 are longerthan the teeth 8 of the roller B. In other words, the roller G will cutan annular path through the material of greater diameter than the pathcut by the roller B and consequently the drill will under-ream a hole orform a hole of greater diameter than the combined cutting area of thedrill. Consequently, the drill will never lose its clearance owing tothe fact that the area of-the cutting surface on one side of thelongitudinal axis of the drill is greater than the area of the cuttingsurface on the other side of the longitudinal axis of the drill. In viewof the fact that the rollers I) and E form a tapered or invertedcone-shaped recess in the bottom of the hole the drill will seat itselfat the center of the hole and will not wabble back and forth when it isin service. This is a very desirable and important feature of my drillfor it insures a circular hole of approximately uniform diameter. If nomeans were provided for holding the drill at the center of the hole thedrill would wabble back and forth and merely form a hole of the samediameter as the distance between the outer edges of the rollers B and C.A tapered or inverted cone-shaped recess is the best means for holding adrill at the center of the hole and as my improved drill is pro videdwith rollers that form such a recess thedrill will under-ream a hole orform a hole of greater diameter than the distance across the cuttingface of the drill, the rollers D and E remaining seated in the taperedrecess at the bottom of the hole and thus holding the roller C in such aposition that it cuts an annular path of greater diameter than the pathcut by the roller B.

The rollers B and C can be retained on the head A in various wayswithout departing from the spirit of my invention but I prefer theconstruction herein shown on account of the fact that it is strong andserviceable and provides a relatively large hear-- ing surface for eachof the rollers B and G. As shown in Fig. 1, the spindles for the rollersB and G each consists of a coneshaped bearing member 10 that fits in acorrespondingly-shaped seat or recess formed in the roller and afastening device 11 that prevents the roller from moving longitudinallyoff of said bearing member 10, said fastening device having ascrew-threaded shank that is screwed into the member 10 and into I thehead A of the drill. At the outer end of the shank of said fasteningdevice is a head 12 which laps over the outer end face of the roller, acircular recess 13 being prefmember 10 constituting removable bearingmembers that can be renewed easily when they become worn. The fasteningdevice 11 holds the roller securely in position, and, if desired, ahollow set screw 16 or other suitable device can be mounted in the headA of the drill so as to lock said fastening device in position.

Lubricating ducts 17 are formed in the head A so as to supply alubricating medium to the bearings of the rollers B, C, D and E, andwater passageways 18 are also formed in the head, as shown in brokenlines in Fig. 1, and in full lines in Fig. 3, so as to discharge streamsof water onto the material whioh the rollers disintegrate and thus flushout the hole, the head A of the drill being provided at its sides withfour notches or cut-out portions 19 up through which the water anddisintegrated material escape. If desired, the removable bearing member10 can be provided with roller bearings 20 or other suitablefriction-reducing devices. as shown in Fig. 4:.

A drill of the construction above-described is strong and rigid owing tothe fact that the head is formed in one piece and the rollers aremounted on the head in such a manner that they arecapable ofsuccessfully withstanding great strains. Comparatively small rollers maybe used for the outer cutting members of the drill, and as the centercutting members also consist of small rollers, the drill can bemanufactured at a low cost.

It is practically impossible for the drill to lose its clearance owingto the fact that it comprises rollers which shear off the material atthe side of the hole, and in view of the fact that center rollers form atapered recess on the bottom of the hole, the drill will remain centeredand thus insure the roller C cutting an annular path of greater diameterthan the combined cutting area across the face of the drill, therebyenabling the drill to be used for under-reaming a hole of approximatelythe same diameter as the head of the drill.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A boring drill comprising a head, means on said head for forming atapered recess at the bottom of the hole so as to center the drill, saidmeans comprising a diametrical cross roller with cutters thereon oflargest 13* diameter at the center of said head, and rollers on saidhead which describe an annular path around said recess, one ofisaidrollers having a cutting surface that projects laterally beyond thedrill-head. 1

2. A boring drill comprising a head, means on said head for forming atapered recess at the bottom of the hole so as to center the drill, saidmeans comprising a diametrical cross roller with cutters thereon oflargest diameter at the center of said head, andj-rollers on said headwhich describe an annular path around said recess, the outer edgeportion of the cutting surface of-one of said rollers being located agreater distance from the longitudinal center of the drill than theouter edge. portion of the cutting surface of the other roller.

3 A boring drill comprising in combination a head, a roller on said headhaving an approximately frusto-conical-shaped cutting portion which isso arranged that it will cut an annular path through the material of,cut the material inside said annular path and for forming a taperedrecess at the bottom of the hole being formed so as to center thedrill.-

4. A boring drill comprising a head, a horizontally disposed shaft onsaid head, a rotatable barrel-shaped cutting means on said shaft ofgreatest diameter at the center of the head and diminishing gradually indiameter toward its ends, and inclined rollers arranged on oppositesides of said shaft and having approximately frusto-conicalshapedcutting portions.

5. A boring drill comprising a head, a horizontally disposed shaft onsaid head, a rotatable barrel-shaped cutting means on said sha'ftofgreatest diameter at the center of the head and diminishing gradually indiameter toward its ends, and rollers arranged on opposite sides of saidshaft and having approximately frusto-conical-shaped cutting portions,the frusto-conical-shaped cutting portion of one of said rollers beingof greater diameter than the corresponding portion of the other roller.

6. A boring drill comprising a head, op-

positely disposed spindles on said head that project downwardly andinwardly toward the longitudinal axis of the head, rollers on saidspindles having approximately frustoconical-shaped cutting portions, andhorizontally disposed rollers arranged between the rollers on saidinclined spindles, said horizontally disposed rollers beingfrustoconical-shaped to form a tapered'recess at the bottom of the holebeing formed.

7. A boring drill comprising a head, two disk shaped cutting rollers onsaid' head having cutting surfaces that act on the side of the hole andcutting surfaces that act on that lie between the rollers on saidspindles,

said last named rollers being of greatest diameter at the center of saidhead.

9. A boring drill comprising a head provided with spindles that inclinedownwardly and inwardly toward the longitudinal center of said head,rollers on said spindles having cutting surfaces that are disposed atapproximately right angles to each other, and a plurality ofhorizontally disposed rollers that lie between the rollers on saidspindles, said horizontally disposed rollers being so shaped that theywill form a tapered recess at the bottom of the hole and one of therollers on saidspindles being of greater diameter than the other roller.

10. A boring drill comprising a head, a substantially cone-shapedbearing member arranged on said head, a roller provided on its undersidewith a pocket for receiving said member, and a fastening devicepassing through said roller and member and screwed into the head andprovided at its outer end with a portion that laps over the end face ofsaid roller.

11. A boring drill comprising a head, a substantially cone-shapedbearing member arranged on said head, a roller provided on its underside with a pocket for receiving said member, and a fastening devicepassing through said roller and member and screwed into the head andprovided at its outer end with a portion that laps over the end face ofsaid roller, the roller being provided in its end face with a recessforreceiving the overlapping portion of said fastening de v1ce.v

12. A rotary boring drill comprising in combination, a head, a crossroller shaft on the forward end thereof, cutters on said shaft, thecutting'surfaces of which are inclined forwardly toward the central axisof the head and inclined cutters on each side of said shaft.

13. A rotary boring drill comprising in combination, two side bearingsat the forward end thereof, a cross roller shaft in said thereof,bearing supports at each end of said recess, a cross roller shaft insaid hearings, rolling cutters thereon adapted to drill a dish-shapedhole to center said drill, and:

cutters mounted on the side faces of said I recess. 3

15. A rotary boring drill comprising in combination, a head, a V-shapedrecess in inserted from the insideof said head and retained in the wallsof said recess.

16. A rotary boring drill comprising in combination, a head, a V-shapedrecess in the forward end thereof, a cutting roller longitudinally ofsaid recess, and disk-shaped side cutters mounted parallel with the sidefaces of said recess, the bearing pins therefor being threaded outwardlyfrom said recess into the side of the head.

In testimony whereof I hereunto affix my.

signature in the presence of two witnesses, this first day of April,1913 HOWARD R. HUGHES.

Witnesses:

WELLS L. CHURCH, GEORGE BAKEWELL.

